JPH0990689A - Electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic device capable of preventing irregular feeding even in the case where the photoreceptor drum of a process unit is in a motion other than rotation while it is rotating. SOLUTION: This device is equipped with a device main body 1, a process unit 11 attachably/detachably attached to the device main body 1 and equipped with a rotatable photoreceptor drum 31 having a rotation transmitting element, and a rotation driving device 17 provided in the main body 1 and equipped with an electric motor 51 and plural stages of rotation transmitting elements 52 to 55 transmitting the rotation of the electric motor to the rotation transmitting element of the drum 31 in the process unit. The rotation transmitting element 55 in the final stage in the rotation driving device directly applies pressure on the rotation transmitting element in contact with the rotation transmitting element of the drum 31 and is provided with means 56 to 59 following the motion other than the rotation of the drum 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus having a detachable process unit.

[0002]

2. Description of the Related Art In a facsimile machine adopting an electrophotographic system, for example, a photosensitive drum, a developing device, a cleaning device and a charging device which constitute an electrophotographic process are combined into a set to form a process unit. There is a device that is detachably attached to the main body of the electrophotographic apparatus.

This is because when the photoconductor drum has reached the end of its life and the time to replace it is set, the other devices are also set to have come to the end of life and are removed together with the photoconductor drum from the main body of the electrophotographic apparatus. It is a method of exchanging. In this process unit, the unit frame rotatably supports the shaft of the photosensitive drum and also supports other devices.

Further, some facsimile machines employ a structure in which an upper lid which can be swung up and down is provided on the upper surface of the main body of the apparatus. This is because the upper lid is always laid down and the upper surface is closed, and when a paper jam or the like needs to be inspected, the upper lid is lifted to open the upper surface, and the device is passed through the upper surface from the outside. This is a method of inspecting the inside of the main body.

In the electrophotographic apparatus adopting this structure, the process unit is inserted into the apparatus main body through the upper surface of the apparatus main body and mounted. this is,
This is because workability when mounting the process unit on the apparatus body and maintenance of the process unit mounted on the apparatus body are convenient.

The electrophotographic apparatus has a rotation driving device for rotating the photosensitive drum of the process unit. Since the process unit is detachably provided in the main body of the apparatus, an electric motor that constitutes the rotation drive device and a gear that is a rotation transmission element that transmits the rotation of the electric motor to the photosensitive drum of the process unit are attached to the main body of the apparatus. . The gears at each of these stages are fixed in position and provided on the apparatus main body. The photoconductor drum is coaxially provided with a gear that is a rotation transmission element that receives rotation from the final stage gear of the rotary drive device.

In the system in which the process unit and the rotary driving device are separable from each other as described above, the following structure has been conventionally adopted in order to combine the process unit and the rotary driving device. The process unit is supported by the device body so that it can be displaced in the vertical direction, and when the upper lid is tilted and rotated, the process unit is pressed and fixed to the device body by the spring provided on the upper lid, and the gear of the photosensitive drum is rotated. The gears at the final stage are in mesh with each other in a state necessary for rotation transmission. When the upper lid is swung up to open the upper surface of the apparatus main body, the spring separates from the process unit and the process unit can be removed from the apparatus main body.

That is, the process unit is positioned by pressing the process unit with a spring to determine the axial distance between the gear of the photosensitive drum and the gear of the rotary drive unit.

[0009]

However, such a conventional electrophotographic apparatus has the following problems.

That is, in the conventional electrophotographic apparatus, the gear of the rotary drive is fixedly provided on the apparatus main body, the process unit is detachably mounted on the apparatus main body, and the process unit is attached to the apparatus main body by the spring provided on the upper lid. To determine the axial distance between the gear of the photosensitive drum and the gear of the rotary drive device.

Even when the process unit is mounted on the main body of the apparatus, when the photoconductor drum is rotated by the rotary drive device, the load torque of the photoconductor drum fluctuates, so that the gear angle of the photoconductor drum depends on the pressure angle. Upward force may work. In this case, the upward force applied to the gear may cause the photosensitive drum to move other than rotate.

When a motion other than rotation of the photosensitive drum occurs in this way, the gears provided on the photosensitive drum also move in the same manner as the photosensitive drum. However, the gears of the rotary drive device are fixed in position and provided in the main body of the device. Therefore, when the gear provided on the photoconductor drum moves, the axial distance between the gear of the photoconductor drum and the final stage gear of the rotary drive device changes according to the movement of the gear of the photoconductor drum.

Here, the rotation speed of the final stage gear of the rotary drive is always constant. From this, if the axial distance between the final stage gear of the rotary drive and the gear of the photoconductor drum changes, the rotation speed of the photoconductor drum changes, and as a result, uneven feeding occurs on the photoconductor drum. It adversely affects photographic recording.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic apparatus capable of preventing the occurrence of uneven feeding even when a motion other than rotation occurs during rotation of the photosensitive drum of the process unit. is there.

[0015]

According to another aspect of the present invention, there is provided an electrophotographic apparatus including an apparatus main body and a process unit including a rotatable photosensitive drum having a rotation transmitting element detachably mounted on the apparatus main body. A rotary drive device having a plurality of stages of rotation transmission elements for transmitting the rotation of the electric motor to the rotation transmission element of the photoconductor drum provided in the main body of the apparatus, and the final stage rotation in the rotation drive device. The transmission element is characterized in that it has means for coming into contact with the rotation transmission element of the photosensitive drum to directly apply pressure to the rotation transmission element, and for following movements other than rotation of the photosensitive drum.

According to this structure, when the photoconductor drum of the process unit makes a motion other than rotation during rotation, the final stage rotation transmission element in the rotary drive unit follows the motion other than the rotation of the photoconductor drum. Then, the state in which the rotation transmitting element of the photosensitive drum is in contact with the pressure is maintained.

For this reason, the rotation of the final stage rotation transmitting element in the rotary driving device is transmitted to the rotation transmitting element of the photosensitive drum without being affected by movements other than rotation of the photosensitive drum, so that the photosensitive drum is kept constant. It can be rotated at a rotational speed. As a result, the rotation speed of the photosensitive drum can be kept constant, uneven feeding can be prevented, and adverse effects on electrophotographic recording can be avoided. The same effect can be obtained even if the movement of the photosensitive drum other than rotation is minute.

That is, while the process unit is detachably mounted on the apparatus main body, and the process unit can be mounted from the upper surface of the apparatus main body, the construction and the maintenance of the process unit are convenient, and the photosensitive drum It is possible to obtain an electrophotographic apparatus in which the rotational speed is kept constant and there is no unevenness in feeding.

According to a second aspect of the present invention, the final stage rotation transmission element in the rotary drive device is a double-sided toothed timing belt wound around a toothed pulley and stretched, and the rotation transmission element of the photosensitive drum is A toothed pulley that meshes with the double-sided toothed timing belt.

According to the present invention, the rotation transmission element of the final stage of the rotation drive device is in contact with the rotation transmission element of the photosensitive drum to directly apply pressure to the rotation transmission element, and other than the rotation of the photosensitive drum. The means for following the movement of can be reliably realized with a simple configuration.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described with reference to the drawings. In this embodiment, the electrophotographic apparatus is applied to a facsimile apparatus. 2 and 3 for the overall configuration of this facsimile apparatus
This will be described with reference to FIG. The electrophotographic apparatus includes an apparatus main body 1 and an upper lid 2 provided above the upper surface of the apparatus main body 1. The upper lid 2 is pivotally supported on the apparatus main body 1 by pivoting means (not shown) so that the upper lid 2 can be swung up and tilted.

When the upper lid 2 is tilted and rotated, the apparatus main body 1
The upper part of the device main body 1 is covered from the upper side by closing the upper part of the device main body 1, and the upper part of the device main body 1 is opened when the device is swung up, and the device provided inside the device main body 1 is taken in and out and maintenance is performed. Inspections can be performed from the open top surface.

The device body 1 is equipped with the following devices. That is, a process unit 11 that employs an electrophotographic system, a recording paper cassette 12 that is located below the process unit 11 and that stores cut recording paper in a stacked manner,
A recording paper feeding / conveying device 13 which is located between the recording paper cassette 12 and the process unit 11 and supplies and conveys the recording paper.
It has. Further, a transfer device 14 facing the photosensitive drum 31 provided in the process unit 11, a fixing device 15 located downstream of the process unit 11 in the recording paper conveyance direction, and a recording paper receiving stand 16 are provided.

Further, although not shown in FIGS. 2 and 3, the apparatus main body 1 is provided with a rotation driving device 17 for rotating a photosensitive drum 31 which will be described later and is provided in the process unit 11 shown in FIG.

As shown in FIGS. 2 and 3, the upper lid 2 is provided with an exposure device 18 and a document transmission device 19 for transmitting the content of the document to the other party. Further, it has a document feed table 20 for setting a document for transmission and a document receiving table 21 for receiving the transmitted document.

As shown in FIGS. 1 and 4, the process unit 11 has a unit frame 11a, and this unit frame 11a is provided with the following device. That is, the photosensitive drum 31, the developing device 32, the cleaning device 33, and the charging device 34, which are rotatably supported by the unit frame 11a, are provided.

The developing device 32 has a device body 35 formed integrally with the unit frame 11a for accumulating toner, an agitator 36, a toner conveying roller 37, a toner supply roller 38, and a toner regulating member 39.

Further, the cleaning device 33 has a device body 40 integrally formed on the unit frame 11a for accumulating toner, a cleaning blade 41 and a toner discharge roller 42.

The process unit 11 configured as described above
As shown in FIG. 3, the upper lid 2 is swung up and the apparatus main body 1
When the upper surface of the device is opened, it can be inserted from the upper side of the device main body 1 through the upper surface part, and taken out from the inside of the device main body 1 through the upper surface part to the outside.

The process unit 11 is removably mounted inside the apparatus main body 1. That is, for example, a protrusion (not shown) is provided on the unit frame 11a, and the protrusion is supported by a receiver (not shown) provided on the apparatus body 1. The receiving portion of the apparatus main body 1 supports the unit frame 11a via the projection so as to be detachable and vertically displaceable. As shown in FIGS. 1 to 3, a pressing spring 22 is provided on the upper lid 2.

When the upper lid 2 is tilted and turned to close the upper surface of the apparatus main body 1, the pressing spring 22 presses a part of the unit frame 11a mounted inside the apparatus main body 1 downward from above, The protrusion of the unit frame 11a is pressed against the receiving portion of the apparatus body 1. Thereby, the unit frame 11a is vertically positioned and fixed to the apparatus main body 1.

The operation of the facsimile apparatus thus equipped with each apparatus will be described. The recording paper supply / conveyance device 13 conveys the recording papers contained in the recording paper cassette 12 one by one between the photosensitive drum 31 of the process unit 11 and the fixing device 15.

The process unit 11 performs the following operation. The photoconductor drum 3 is driven by a rotary drive device 17 described later.
1 is rotated in the direction of the arrow in FIG. Further, the developing device 32
Each of the rollers 37 and 38 is rotated by receiving, for example, rotation from the photosensitive drum 31 or rotation from another rotation driving device (not shown) provided in the apparatus main body 1.

The charging device 34 charges the surface of the photosensitive drum 31. The exposure device 18 exposes an image based on the received signal on the surface of the charged photosensitive drum 31 to form an electrostatic image.

In the developing device 32, the toner accumulated in the device main body 35 is conveyed to the toner supply roller 38 by the toner conveyance roller 37, and the toner supply roller 38 forms a thin layer of the toner on the toner regulating member 37 of the photosensitive drum 31. Supply to the surface. As a result, a toner image is formed on the surface of the photosensitive drum 31.

Then, the transfer device 14 transfers the image on the photosensitive drum 31 to the recording paper passing between the photosensitive drum 31 and the transfer device 14 by the recording paper supply / transport device 13. The cleaning blade 41 of the cleaning device 33 removes the toner remaining on the photosensitive drum 3 after the transfer and collects the toner in the device body 40. The toner image is fixed on the recording paper after the transfer by the fixing device 15, and the recording paper is conveyed to the recording paper receiver 16.

Next, the rotation driving device 17 provided in the apparatus main body 1 and the rotation transmitting element provided in the photosensitive drum 31 which are the features of the present invention will be described with reference to FIGS. 1, 5 and 6.

The rotary drive unit 17 has the following components as shown in FIG. That is, the electric motor 51,
A first-stage transmission gear 52 mounted on the output shaft 51a of the electric motor 51, a second-stage transmission gear 53 meshing with the first-stage output gear 52, and a third gear meshing with the second-stage output gear 53. It has a stage transmission gear 54 and a fourth stage transmission gear 55 meshing with the third stage output gear 53. The electric motor 51 and the gears 53 and 54 are rotatably supported by the apparatus main body 1.

As the final stage rotation transmission element in the rotary drive unit 17, a double-sided toothed timing belt 56 is provided below one end of the photosensitive drum 31 in the process unit 11. The timing belt 56 is an endless belt formed of an elastic material, and has teeth 56a and 56b formed on the inner surface and the outer surface on both sides as shown in FIG. ing.

The timing belt 56 is shown in FIGS.
As shown in (a) and (b), the drive pulley 57 and the auxiliary pulleys 58 and 59 are wound around and stretched. The drive pulley 57 and the auxiliary pulleys 58 and 59 have teeth 57a, 58a and 59a on the outer peripheral portions as shown in the enlarged portion A of FIG. Drive pulley 57 and auxiliary pulleys 58, 5
9 is rotatably supported by the apparatus main body 1, and a drive pulley 57 is provided with a fourth stage transmission gear 55 coaxially.
The timing belt 56 has teeth 56a formed on the inner surface thereof and has teeth 57a, 58a, 59 of the respective pulleys 57, 58, 59.
a. As a result, the timing belt 56 is rotatably supported by the drive pulley 57 and the auxiliary pulleys 58 and 59. 1 and 6 (a) and 6 (b), the timing belt 56, the drive pulley 57, and the auxiliary pulleys 58 and 59 are omitted except for the enlarged portion A in FIG.

Drive pulley 57 and auxiliary pulleys 58, 5
The numeral 9 gives tension to the timing belt 56 to support it in a tensioned state so as to form a triangle. One side of the timing belt 56 is located on the upper side, and the process unit 1
1 is positioned horizontally so as to come into contact with a pulley 60 provided at one end of the photosensitive drum 31 described later. When an external force is applied to the timing belt 56, the timing belt 56 is elastically bent in accordance with the state of the external force to maintain a tension state. In this way, the final stage rotation transmission element in the rotation drive device 17 is configured.

Further, as shown in FIG. 5, one end of the photosensitive drum 31 in the process unit 11 is coaxially provided with a toothed pulley 60 which is a rotation transmitting element. The pulley 60 has a peripheral portion 60a. The teeth 60a are provided on the drive pulley 57 and the auxiliary pulleys 58 and 59.
The teeth 56b on the outer surface of the timing belt 56 supported by.

If the process unit 11 is not attached to the apparatus main body 1 as shown in FIG.
The timing belt 56 is elastically tensioned to form a triangle. When the process unit 11 is attached to the apparatus main body 1 as shown in FIGS. 1 and 6B, the pulley 60 of the photoconductor drum 31 contacts a horizontal side portion of the timing belt 56, and the side portion is fixed. Push down.
That is, the horizontal one side portion of the timing belt 56 is located at a position higher than the lower side of the pulley 60 of the photosensitive drum 31 when the process unit 11 is mounted on the apparatus main body 1. The timing belt 56 is the tooth photosensitive drum 31.
Set up the positional relationship with and stretch.

Therefore, when the process unit 11 is mounted on the apparatus main body 1, the timing belt 56 is elastically pushed by the pulley 60 of the photosensitive drum 31 and bent downward. That is, the timing belt 56 is in mesh with the pulley 60 to directly apply pressure. From this, the timing belt 56 bends according to the height position of the pulley 60 of the photosensitive drum 31, and contacts the pulley 60.

The operation of the rotary drive device 17 thus constructed will be described. The electric motor 51 is driven to rotate its rotation from the first transmission gear 52 to the gears 53, 54, 55 of each stage.
To the drive pulley 57 to rotate the drive pulley 57. The rotation of the drive pulley 57 causes the timing belt 56 to rotate. The auxiliary pulleys 58 and 59 rotate together with the timing belt 56, and the timing belt 56 is wound around the drive pulley 57 and the auxiliary pulleys 58 and 59 and stretched to rotate. The pulley 60 is rotated by the rotation of the timing belt 56, and the photosensitive drum 31 is rotated together with the pulley 60.

When there is a movement other than the rotation of the photosensitive drum 31, that is, a vertical direction, a horizontal direction, or a combination of these directions, the timing belt 56
Bends so as to absorb the movement of the photoconductor drum 31, and applies pressure as in the case where there is no movement to maintain the state of being in contact with the pulley 60. The same operation is performed even if the movement of the photosensitive drum 31 is minute.

Therefore, the rotation of the timing belt 56 at the final stage in the rotation driving device 17 is transmitted to the pulley 60 of the photosensitive drum 31 without being affected by movements other than the rotation of the photosensitive drum 31, so that the photosensitive drum 31 is rotated. 31 can be rotated at a constant rotation speed. This makes it possible to keep the rotational speed of the photosensitive drum 31 constant, prevent uneven feeding, and avoid adversely affecting electrophotographic recording.

Therefore, according to this embodiment, the process unit 11 can be removably mounted on the apparatus main body 1, and the process unit 11 can be mounted from the upper surface of the apparatus main body 1 so that the process unit 11 can be mounted and maintained. While adopting a convenient structure, it is possible to realize an electrophotographic apparatus having a uniform rotation speed of the photoconductor drum 31 and having no uneven feeding.

Further, in this embodiment, the toothed pulley 57 is used as the final stage rotation transmission element of the rotary drive unit 17.
It is a timing belt 56 with double-sided teeth wound around and stretched around 59 to 59, and a rotation transmission element of the photosensitive drum 31 is a toothed pulley 60 meshing with the double-sided toothed timing belt 56. The timing belt 56 flexibly absorbs minute movements of the photoconductor drum 31 and always reliably contacts the pulley 60, and the rotation of the rotary drive device 17 can be reliably transmitted to the pulley 60.

Therefore, in addition to the rotation transmission element of the photoconductor drum 31 included in the final stage rotation transmission element of the rotary drive device 17, a pressure is directly applied to the rotation transmission element, and the rotation transmission element other than the rotation of the photoconductor drum 31 is rotated. The means for following the movement can be reliably realized with a simple configuration.

The present invention is not limited to the above-described embodiments, but can be modified in various ways.

The final stage rotation transmitting element in the rotation driving device 17 is not limited to the above-mentioned embodiment. For example,
The configuration described below can be adopted. A swing arm that swings in the direction in which the timing belt 56 is stretched and loosened is provided, and either one of the auxiliary pulleys 58 and 59, for example, the auxiliary pulley 58, is attached to this swing arm, and the timing belt is attached to this swing arm. Apply a spring force in the direction to stretch 56. Therefore, the swing arm is always inclined in the direction in which the timing belt 56 is stretched. When the pulley 60 of the photosensitive drum 31 comes into contact with the timing belt 56, an external force thereof swings through the timing belt 56 and the auxiliary pulley 58 in a direction in which the swinging arm loosens the timing belt 56 against the spring force of the spring. To do. As a result, the timing belt 56 follows movements other than the rotation of the photosensitive drum 31.

Further, the configuration shown in FIG. 7 can be adopted as the final stage rotation transmission element in the rotation drive device 17. That is, the rotation drive device 17 has a first stage transmission gear 71, a second stage transmission gear 72, and a final stage transmission gear 73, which sequentially mesh to perform rotation transmission. A transmission gear 74 that meshes with the transmission gear 73 is provided as a rotation transmission element of the photosensitive drum 31. A rotary arm 75 supported by the rotary shaft of the second stage transmission gear 72, which is the stage before the final stage, is provided, and the final stage transmission gear 73 is attached to the tip of the rotary arm 75. The rotating arm 75 rotates in the vertical direction about the rotation axis of the second stage transmission gear 72. Further, the spring 76 applies an elastic force to the rotating arm 75 in the upward direction to approach the photoconductor drum 31.

As a result, when the process unit 11 is not attached to the apparatus main body 1 as shown in FIG.
The rotating arm 75 is pulled upward by a spring 76. As shown in FIG. 7B, when the process unit 11 is attached to the apparatus main body 1, the transmission gear 74 of the photoconductor drum 31.
Meshes with the transmission gear 73. At this time, the transmission gear 74 pushes down the transmission gear 73. Due to this pushing down force, the rotating arm 75 rotates downward against the force of the spring 76 and moves the transmission gear 73 downward. As a result, the transmission gear 73 constantly meshes with the transmission gear 74 with pressure, and follows the movement of the photoconductor drum 31 other than rotation to maintain the contact state.

[0055]

According to the electrophotographic apparatus of the first aspect of the present invention, when the photosensitive drum of the process unit makes a motion other than rotation during rotation, the final stage rotation transmitting element in the rotary drive unit is exposed to light. Following a movement other than rotation of the body drum, the state in which the rotation transmission element of the photoconductor drum is in pressure contact is maintained. Therefore, it is possible to prevent the photosensitive drum from being affected by movements other than rotation, keep the rotational speed of the photosensitive drum constant, prevent uneven feeding, and avoid adversely affecting electrophotographic recording. it can.

Therefore, according to the first aspect of the present invention, the process unit can be removably attached to the apparatus main body, and the process unit can be attached from the upper surface of the apparatus main body.
It is possible to obtain an electrophotographic apparatus having a uniform feeding speed while keeping the rotation speed of the photosensitive drum constant while adopting a configuration in which mounting and maintenance of the process unit is convenient.

According to the second aspect of the present invention, the rotation transmission element of the final stage of the rotation drive device is in contact with the rotation transmission element of the photosensitive drum to directly apply pressure to the rotation transmission element, and at the same time, the photosensitive drum is provided. The means for following movements other than rotation can be reliably realized with a simple configuration.

[Brief description of drawings]

FIG. 1 is a sectional view showing a process unit and a rotation transmission device of an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an electrophotographic apparatus according to the same embodiment.

FIG. 3 is a cross-sectional view showing the electrophotographic apparatus according to the same embodiment.

FIG. 4 is a sectional view showing a process unit of the electrophotographic apparatus according to the same embodiment.

FIG. 5 is a perspective view showing a rotation driving device of the electrophotographic apparatus according to the embodiment.

FIG. 6 is an explanatory diagram showing a rotation driving device of the electrophotographic apparatus according to the embodiment.

FIG. 7 is an explanatory diagram showing a rotation driving device of an electrophotographic apparatus according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Device main body, 2 ... Upper lid, 11 ... Process unit, 17 ... Rotation drive device, 31 ... Photosensitive drum, 51 ... Electric motor, 52 ... Gear, 53 ... Gear, 54 ... Gear, 55 ... Gear, 56 ... Timing Belts, 57 ... pulleys, 58 ... pulleys, 59 ... pulleys, 60 ... pulleys.

Claims (2)

[Claims] 1. A process unit including an apparatus main body, a rotatable photosensitive drum having a rotation transmission element detachably attached to the apparatus main body, an electric motor provided in the apparatus main body, and rotation of the electric motor. And a rotation driving device having a plurality of stages of rotation transmitting elements for transmitting to the rotation transmitting element of the photoconductor drum, wherein the final stage rotation transmitting element of the rotation drive device is in contact with the rotation transmitting element of the photoconductor drum. While directly applying pressure to this rotation transmission element,
An electrophotographic apparatus comprising means for following a movement other than the rotation of the photosensitive drum. 2. The final stage rotation transmission element in the rotary drive device is a timing belt with double-sided teeth wound around a pulley with teeth and stretched, and the rotation transmission element of the photosensitive drum is the double-sided teeth. The electrophotographic apparatus according to claim 1, wherein the electrophotographic apparatus is a toothed pulley that meshes with an attached timing belt.